HDNL Toy

import java.util.ArrayList;
import java.util.Scanner;
import java.util.Stack;

public class HDNLToy2 {
    public static Scanner scanner = new Scanner(System.in);

    public static void main(String[] args) {
        ArrayList<String> list = new ArrayList<>();
        int n = Integer.parseInt(scanner.nextLine());

        for (int i = 0; i < n; i++) {
            list.add(scanner.nextLine());
        }

        indentationStation(list);
    }

    public static void indentationStation(ArrayList<String> list) {
        Stack<String> stack = new Stack<>();
        int numberOne;
        int numberTwo;
        stack.add(list.get(0));
        System.out.printf("<" + stack.peek() + ">%n");
        for (int i = 1; i < list.size(); i++) {
            numberOne = Integer.parseInt(list.get(i).substring(1));
            numberTwo = Integer.parseInt(list.get(i - 1).substring(1));
            if (numberOne > numberTwo) {
                stack.add(list.get(i));
                System.out.printf("%1$" + (Math.max(stack.size() - 1, 1)) + "s<" + stack.peek() + ">%n", "");
            } else {
                if (!stack.isEmpty()) {
                    while (!stack.isEmpty()) {
                        int numberThree = Integer.parseInt(stack.peek().substring(1));
                        if (numberThree >= numberOne) {
                            System.out.printf("%1$" + (Math.max(stack.size() - 1, 1)) + "s</" + stack.peek() + ">%n", "");
                            stack.pop();
                        } else {
                            stack.add(list.get(i));
                            System.out.printf("%1$" + (Math.max(stack.size() - 1, 1)) + "s<" + stack.peek() + ">%n", "");
                            break;
                        }
                    }
                    if (stack.isEmpty()) {
                        stack.add(list.get(i));
                        System.out.printf("<" + stack.peek() + ">%n");
                    }
                } else {
                    stack.add(list.get(i));
                    System.out.printf("s<" + stack.peek() + ">%n");
                }
            }
        }
        if (!stack.isEmpty()) {
            int numberFour = stack.size();
            for (int i = 0; i < numberFour; i++) {
                System.out.printf("%1$" + (Math.max(stack.size() - 1, 1)) + "s</" + stack.pop() + ">%n", "");
            }
        }
    }
}